Recently, due to an increase in emissions of carbon dioxide caused by consumption of fossil fuels, a sudden change in crude oil price, or the like, development of a technology of converting a vehicle energy source from gasoline or diesel into electric energy has been spotlighted. Practical use of an electric vehicle has proceeded, and for long distance driving, a lithium ion battery, which is a storage battery, should have a large capacity and high energy density. However, in a current lithium ion battery, there is a limitation in a battery capacity, such that the long distance driving may be difficult. Therefore, a lithium air battery theoretically having larger capacity and higher energy density than those of the lithium ion battery has been spotlighted.
In general, the lithium air battery includes an anode capable of adsorbing and emitting lithium ions and a cathode containing an oxidation reduction catalyst of oxygen using oxygen in the air as a cathode active material, and a lithium ion conductive medium is provided between the cathode and anode.
The lithium air battery has a theoretical energy density of 3000 Wh/kg or more, which corresponds to about 10 times energy density of the lithium ion battery. In addition, the lithium air battery may be eco-friendly and provide improved stability as compared to the lithium ion battery.
The lithium air battery, which is a battery having a cathode using oxygen in the air as an active material, may be charged and discharged by performing an oxidation reduction reaction of oxygen in the cathode.
In a lithium air battery according to the related art, polarization was generated by a high over-voltage at the time of charge and discharge, such that energy efficiency at the time of charge and discharge was significantly low as compared to the lithium ion battery. Therefore, a lithium air battery capable of improving energy efficiency at the time of charge and discharge has been demanded.
In order to solve the above-mentioned problem, according to the related art, a lithium air battery has been disclosed in U.S. Patent Application Publication No. 2012/0028164 (hereinafter, referred to the Related Art Document 1). However, in the lithium air battery disclosed in the Related Art Document 1, chemical characteristics of an electrolyte are improved, but there is a limitation in improving charge and discharge performance of the lithium air battery, and since the coupling is not firm, durability may be deteriorated.